This invention relates to the construction of respirators in general and, in particular, to a new and useful respirator, particularly adaptable for use by persons working or moving in high temperature areas and areas which may contain contaminated breathing air.
The present invention is an improvement over German Pat. No. 2,700,492 (DE-AS No. 27 00 492), corresponding to U.S. Pat. No. 4,188,947, for "RESPIRATOR WITH A COOLING DEVICE". The invention is an improvement over the disclosure of the aforementioned patent dealing with a respirator having a chemical cartridge for the absorption of exhaled carbon dioxide and for the formation of oxygen which may be added to the respiratory air and which also includes a cooling device. In this patent, the coolant is contained in a coolant bag accommodated in the space between a contact wall of the breathing bag and the equipment wearer's back.
Except for the contact surface with the contact wall, the coolant bag may be enclosed in an insulating layer. The coolant bag has a filler nipple with a closure at its bottom. The closure contains one or more gas discharge tubes extending towards the breathing bag. The gas which is freed when the coolant warms up flows through these tubes in the direction toward the breathing bag, where it mixes with the outside air in the respirator and circulates around the breathing bag and the chemical cartridge, thus cooling the outside air. Cooling only the back of the wearer may lead to possible local undercooling despite the presence of the insulating layer and the kidneys, for example, may become overstressed.